Exactly. They aren't being sued for infringement, but for fees. Believe me, the musical licensing folks are ruthless.
Which one recently tried to sue the Girl Scouts for singing songs around the campfire, until public opinion dissuaded them?
Yes, you are right about ruthless collection of royalties by performing rights organizations. Broadcast Music Inc. (BMI) is one of them. I co-wrote a song that has been played regularly for more than eight years on a nationally syndicated talk show. BMI has stiffed me and my co-writer. We have never been paid a cent and we have angrily demanded payment because we know damn well BMI collects from EVERYBODY they can find playing music. These rights organizations mostly are a scam. They collect a lot and pay little and late, if at all.